I've not had the chance to meet David Cohen (yet) but am a fan of his blog ColoradoStartups. 

You should read his "Plenty of time for that later" post from which I am going to lift a passage to share here:

"So, if you’re thinking about doing a startup that you’re really
jazzed about, and are trying to decide if now or later is the time,
here’s my advice. Look at the clock on your computer, and make a note
of the current time and date. Hang that note on your desk or on a wall
somewhere where you will see it every day. Now, ask yourself if you
want to watch the days, weeks, months, and years slip by while your
dream just hangs there on the wall or if you want to do something about
it.

If you passionately want to do something about something, now is the time. Later is just an excuse."

Great words David.

I'll be in Boulder later this month and maybe will actually be able to meet David in person during my visit.